1. Field of the Invention
This invention relates to a process for applying a piece to a sheet material web in making a bag of heat-sealable plastic film which has a mouth constructed to be heat-sealed initially and has a bag mouth closure including a patch bonded to the bag mouth and bendable in two return bends with the bag mouth lips for reclosing the bag mouth securely after the seal has been parted.
2. Prior Art
Apparatus for making heat-sealable bags of plastic film heat-sealable material are shown in U.S. Pat. Nos. 3,553,933 issued Jan. 12, 1971; 4,288,967 issued Sept. 15, 1981; and 4,288,968 issued Sept. 15, 1981. Such patents, however, do not show apparatus for applying a piece to a sheet for forming a reclosable closure for bags.
The apparatus of the present invention applies a patch piece to a web of plastic film heat-sealable material from which a bag is made. Apparatus for applying a piece to a web of wrapping material is shown in U.S. Pat. No. 3,431,827, issued Mar. 11, 1969, but that apparatus is rather complex and cumbersome and may not operate satisfactorily.